Absorption of vitamin B12 is a complex process that relies heavily on a healthy, intact gastrointestinal system. Contact time in the stomach and upper region of the small intestines is particularly important, thus individuals who have undergone bariatric surgical procedures may be particularly prone to deficiency. Deficiency of B12 can lead to conditions such as anemia, nervous system dysfunction, and cardiovascular disease.

Sublingual (under-the-tongue) supplementation of B12 has been shown to provide good protection against B12 deficiency, and can be an excellent alternative to or addition to periodic injections.